Electromagnetic pump



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FIP85D2 R. J. CAMPANA ELECTROMAGNETIC PUMP Dec. 31, 1963 3 Sheets-Sheet 1 Filed April 14, 1961 R. J. CAMPANA ELECTROMAGNETIC PUMP Dem 31, 1963 3 Sheets-Shani, 2

Filed April 14. 1961 Dec. 31, 1963 R. J. CAMPANA 3,115,837

ELECTROMAGNETIC PUMP Filed April 14. 1961 3 Sheets-Sheet 3 W/ A'Q 3 EEHIIIIIEH frwmw United States Patent G 3,115,837 ELECTROMAGNETIC PUMP Robert J. Campana, Solana Beach, Calif., assignor to General Dynamics Corporation, New York, N.Y.,. a corporation of Delaware Filed Apr. 14, 1961, Ser. No. 103,088 4- Claims. (Ci. 103--1) This invention relates to electromagnetic pumps and more particularly to a direct-current conduction type electromagnetic pump.

Various types of direct-current electromagnetic pumps have been developed heretofore. For the most part, these devices function in substantially the same manner and include certain basic elements. Among these basic elements are (1) an electromagnet which is constructed of a ferromagnetic material and which establishes a magnetic field through a pumping section of a fluid carrying duct and (2) a pair of rather heavy electrode members (i.e., copper bus bars) which are secured to,the pumping section of the duct to provide a path for current flow to and through the electrically conductive fluid disposed in the magnetic field.

While the previously developed electromagnetic pumps are suitable for pumping liquid metals under normal operating conditions, such devices are often limited to operation within a specific temperature range. Accordingly, such devices have not been suitable for use in circulating high temperature metalized reactor coolants inasmuch as the ferromagnetic core material is adversely affected by the loss of ferromagnetism that results when the Curie point of the material is approached or exceeded. Another limitation imposed upon these devices results from the use of heavy copper conductors or the like for supplying current to the pumping section of the fluid carrying duct. These heavy conductors or bus bar members preclude the use of such a device in airborne installations or in vehicles designed for space travel wherein the matter of weight is of great significance.

Accordingly, it is a prime object of the present invention to provide a new and improved direct-current electromagnetic pump.

Another object of the present invention is to provide a lightweight and compact electromagnetic pump which is suitable for circulating high temperature reactor coolants.

A further object of the invention is the provision of a conduction type electromagnetic pump which is both compact and lightweight and extremely suitable for use in any number of airborne or space applications.

A further object of the invention resides in the provision of a direct-current conduction type pump which can function effectively over a wide range of temperatures.

A more finite object of the present invention is to provide a conduction type electromagnetic pump which utilizes lightweight, air or vacuum core materials to establish a force producing magnetic field and effect the pumping of high temperature liquid metals.

Other objects and advantages of the present invention will become apparent from the following description of a preferred embodiment of the invention when considered in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a perspective view of a conduction type electromagnetic pump embodying the principal features of the present invention;

FIGURE 2 is a plan view, partially in section, of the pump illustrated in FIGURE 1;

FIGURE 3 is a vertical cross-sectional view taken along the line 3--3 of FIGURE 2;

FIGURE 4 is a vertical cross-sectional view of the ing section of the duct.

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electromagnetic pump taken along the line 4-4 of FIG- URE 2;

FIGURE 5 is a horizontal cross-sectional view taken along the line 55 of FIGURE 3;

FIGURE 6 is a perspective view illustrating the-pumping section of the fluid carrying duct utilized in conjunction with the electromagnetic pump;

FIGURE 7 is a perspective view illustrating one of a pair of current carrying conductors which is welded to, and utilized in conjunction with, the fluid carrying duct depicted in FIGURE 6;

FIGURE 8 is a perspective view of another of the current carrying conductors for the electromagnetic P p;

FIGURE 9 is a perspective view of a field coil assembly of the type utilized in a preferred embodiment of an electromagnetic pump illustrated in the other drawings;

FIGURE 10 is a simplified equivalent electrical circuit for the pump disclosed in FIGURES 1 through 9, inclusive;

FIGURE 11 illustrates another embodiment of a conduction type electromagnetic pump embodying the principal features of the present invention; and

FIGURE 12 is a vertical cross-sectional view taken along the line 1212 in FIGURE 11.

As illustrated in FIGURES 1 through 10, a first embodiment of an electromagnetic pump incorporating the principal features of the present invention includes the series-parallel combination of a plurality of pump components which coact to impart a substantial longitudinal force or thrust to a liquid medium being carried through a thin walled pumping section of a duct or fluid conveying member that is structurally associated with these components. A magnetic field is produced by the passage of direct current through a Helmholtz type field coil assembly consisting of two spaced apart air or vacuum core field coils which are disposed on opposite sides of the pumping section of the duct. The current supplied to the field coils subsequently passes through a first conduc tive member which is serially connected to the coils and the pumping section of the duct. This current passes through the fluidized metal confined in the pumping section and is returned by a second conductive member to the source or current supply.

The generated magnetic field is directed normal to the path defined by the metalized fluid flowing in the pump- Similarly, the passage of current through the duct is perpendicular to the direction of fluid flow and, in addition, is normal to the magnetic field. The resulting coaction of the mutually perpendicular magnetic field and current flow imparts a longitudinal thrust or force to the current carrying liquid thereby resulting in the desired pumping operation.

Referring to FIGURE 1, a preferred embodiment of an electromagnetic pump, which is generally designated by the numeral 20, functions to pump a supply of a liquid metal (i.e., lithium) from a source thereof (not shown) through a conduit member 21. More particularly, the pumping action effected by the pump 20 results in the liquid metal being drawn from the source through the conduit member 21 and a pumping duct or member gen erally designated by the numeral 22 and being fed to another conduit member 23. As illustrated in FIGURE 6, the duct 22 includes a pair of converging connecting members or channels 22a, which are attached to the tubular supply lines 21 and 23, and a pumping section 2212, which may be constructed in any desired configuration. In the illustrated embodiment, the pumping section 2212 is a generally rectangular thin walled section having a width substantially greater than the diameter of the tubular supply lines.

Mounted above and below the pumping section 22b of the duct 22 are a pair of air or vacuum core field coils 24 and 26, consisting of one turn each. The field coils 24 and 26 form a part of a Helmholtz type field coil assembly of the type illustrated in FIGURE 9 and generally designated by the numeral 27. The field coils 24 and 26 are substantially circular members which extend from a positive or current input terminal 23 to a negative or current output terminal 29. The terminals 28 and 29 are spaced a short distance from each other, and each extends between the upper and lower field coils 24 and 26. As shown in FIGURE 9, the coils are separated to provide a space sufficiently large to accommodate the rectangular pumping section 22b of the duct and a pair of current carrying conductive members associated therewith.

Current supplied to the positive terminal 28 from a generator 30 passes through the parallel paths provided by the field coils 24 and 26 to the negative terminal 29. Consequently, an axial magnetic field is created in the cylindrical area defined by the inner radius of each of the field coils 24 and 26. This field will be directed downwardly and normal to the plane of the pumping section 22b which is mounted between the field coils. The distance separating the upper and lower field coils is selected so as to confine the radial distribution of the field established therebetween and thereby concentrate the flux within the cylindrical region defined by the inner radius of the upper and lower field coils.

As clearly illustrated in FIGURES 3, 4 and 9, the field coil assembly is preferably constructed with a rectangular cross-section which is divided into four individual sections by vertical and horizontal wall members 31 and 32, respectively. These sections of the field coils 24 and 26 and of the terminals 28 and 29, which are defined by the thin outer walls and the wall members 31 and 32, are filled with a light-weight conductive medium 33 such as lithium metal.

Secured to the opposite edges of the pumping section 2217, which is mounted between the field coils, are a pair of conductive members 36 and 37 (FIGURES 7 and 8). A first of these conductive members, namely, the member 36, is mounted below the pumping section of the duct as illustrated in FIGURE 1. This conductive member, which is rectangular chamber constructed of a substantially nonconductive material such as niobium, is filled with lithium metal or other suitable conductive medium in a manner analogous to that described in conjunction with the field coils 24 and 26.

That portion of the chamber 36 which extends across the lower surface of the pumping section 2212 is insulated from the pumping section by a suitable insulating substance (i.e., alumina). The edge of the chamber 36 that projects from beneath the pumping section toward the terminals 28 and 29 is maintained in electrical contact with the terminal 29 but is apertured to allow the terminal 28 to pass therethrough without contacting the chamber. The opposite L-shaped edge portion or connector 36a of the chamber or conductive member 36 extends upwardly along the edge of the pumping section and is welded thereto and maintained in electrical contact therewith.

The second conductive member 37, which in a preferred embodiment of the invention is also a light-weight niobium chamber filled with lithium\metal, is welded and electrically connected to the edge of the pumping section oppositely disposed to that whereto the L-shaped edge of the chamber 36 is secured. This member or chamber 37 is apertured so that each of the terminals 28 and 23 of the field coils pass therethrough and do not contact the member. In addition, the first conductive member or chamber 36 and the member 37 are spaced apart at the projecting portions thereof and are insulated from each other.

The conductive member 37 serves to complete a path for current flow which is supplied to the positive or input terminal 28 of the field coils. Accordingly, a complete series-parallel path for current fiow from a source (not shown) is provided by the field coils, chambers and liquid coolant confined within the pumping section of the duct. More particularly, current supplied to the input terminal 28 flows through the metal medium confined in the field coils 24 and 26, the conductive member or chamber 36, and through the fluid medium within the pumping section 22b to the second conductive member or chamber 37.

The field coils 24- and 26 and the conductive members 36 and 37 are hollow chambers having walls of uniform thickness. The metal medium confined therein conducts substantially all of the current supplied to these members because of the greater conductivity of the latter. The adjacent electrically connected field coils and conductive members are welded together and the current passing through the confined metal medium passes through the walls of the joined members at the welded surfaces thereof and is thereafter concentrated within the highly conductive confined medium.

The operation of the electromagnetic pump and the manner in which the pumping of liquid metals is effected thereby will best be understood when considered in conjunction with the equivalent electrical circuit for the pump as illustrated in FIGURE 10.

Current supplied to the input terminal 28, which is represented in FIGURE 10 as a conductor 41, passes through parallel paths provided by the metal medium confined in upper and lower field coils 24 and 26. These single turn coils 24 and 26 are represented by a pair of resistors 42 and 43. The concomitant passage of current through the field coils creates an axial magnetic field which passes through the pumping section of the duct 22 in a direction substantially perpendicular thereto. This magnetic field constitutes one of the thrust producing components which effects the passage of the liquid metal coolant from the conduit member 21 to the conduit member 23.

As previously described, the current passed through the parallel paths provided by the field coils 24 and 26 thereafter is passed through the first conductive member or chamber 36. This member or chamber is represented by a resistor 44 in FIGURE 10.

Current supplied to the first conductive member, which is mounted below the pumping section 221) of the duct, passes through the metal medium contained therein. The insulating material separating the conductive member 36 and the pumping section of the duct precludes the passage of current therebetween except at the edge portion of the duct whereat the L-shaped connecting section of the chamber is welded and electrically connected to the duct.

Thereafter, current is passed through the pumping section of the duct and the liquid metal medium passing therethrough. Inasmuch as the direction of current flow through the fluid in the duct 22 is opposite to that passing through the first conductive member 36, each of the corresponding generated magnetic fields compensates for the other.

The path for current flow through the pumping section of the duct is represented by the parallel arrangment of components 46 through 49 in FIGURE 10. The resistor 46 in this parallel combination of components represents the resistance of the liquid confined in and being passed through that portion of the pumping section 2211 of the duct whereto the conductive members 36 and 37 are secured. The voltage source 49, which is connected in series with the resistor 46, represents the counter that is developed due to the passage of the conductive liquid metal through the magnetic field. The resistor 47, which is connected in parallel with the serially connected elements 46 and 49, represents the resistance of the walls of the pumping section of the duct between the conductive members 36 and 37. The remaining parallel resistor 48 represents miscellaneous impedance components to the flow of current from the first conductive member to the second conductive member. Among other hings, these components include the resistance of the pumping section walls wherethrough current ilows when by-passing the region between the conductive members 36 and 37 and losses due to mismatch of the current and flux distributions.

The passage of current through the pumping section of the duct, and more particularly through the liquid metal medium therein, supplies the second thrust producing component which results in the desired pumping tqaction. This current component, which is substantially normal to the magnetic field previously generated, coacts with the magnetic field generated by the field coil assembly so that a longitudinal thrust is imparted to the metal medium. The liquid metal medium, wherethrough the current passes during the interval of time the liquid is confined in the pumping section is analogous to a current carrying conductor disposed in a magnetic field which is moved relative thereto by the coaction of the field with the moving charges carried by the conductor.

In a specific embodiment of the invention, the fluid carrying passage provided in the pumping section 22b of the duct 22, which is constructed of niobium metal, is approximately 1 cm. high, cm. wide and 60 cm. in length. The structural stability of the pumping section is enhanced by a plurality of vertical wall members which are mounted within the fluid carrying member and divide the passage into a plurality of parallel channels. The conduit members 21 and 23, which are welded to the pumping section by the members 22a, have a diameter of approximately 8 cm.

The field coils 24 and 26, which are mounted above and below the pumping section of the duct, have a mean radius of approximately 25 cm. and are separated a distance of approximately 8 cm. This spacing allows the pumping section and the current carrying members welded thereto to be readily mounted between the field coils and substantially confines the radial distribution of the axial magnetic field to the area occupied by the pumping sec tion of the duct.

The first conductive member 36, which is mounted below and insulated from the pumping section 22b except at the connecting edge portion thereof, is approximately cm. in length and has a single aperture provided therein which precludes the engagement of this member with the positive or input terminal 28 of the field coil assembly 27. The second conductive member 37, which is approximately cm. in length, is also apertured; however, in this instance, the aperture is proportioned so as to preclude the engagement of either the terminal 28 or 29 with the member.

FIGURES l1 and 12 illustrate an alternate embodiment of the electromagnetic pump previously described. While the two embodiments function in substantially the same manner, the pump illustrated in FIGURES 11 and 12 utilizes a somewhat differently constructed pumping section and a modified arrangement of pump components. However, due to the similarity between various specific features of the two pumps, like but primed reference numerals will be used in the following description of this alternate embodiment to identify the various pump components which substantially correspond to those utilized in the previously described embodiment.

Accordingly, the electromagnetic pump 20' illustrated in FIGURE 11 includes a pumping duct 22' which carries a supply of liquid metal that is to be pumped from a conduit member or tubular supply line 21 to a tubular supply line 23'. The tubular supply lines 21 to 23 communicate with the pumping duct 22' through a pair of converging connecting members or channels 22a. The connecting channels 22a are connected to a pair of spaced apart pumping sections 2212'.

The pumping sections 22b constitute a continuous segment of pumping duct that provides a series path for the metallic medium being pumped therethrough. A curved or reversing segment 220' of the pumping duct 22' joins the pumping sections 22b and effects a reversal in the flow of the metallic medium carried therein through a magnetic field generated by a pair of air or vacuum core field coils 24 and 26'.

Each of the field coils 24' and 26' preferably consists of one turn. The field coils are electrically connected to provide parallel paths for current flow therethrough and are mounted above and below the spaced apart pumping sections 22b so as to insure maximum flux distribution therethrough. As illustrated in FIGURE 11, the field coils are positioned between the converging connecting members 22a and the curved or reversing segment 22c of the pumping duct 22'.

A pair of conduit members 36' and 37' are joined by a suitable welding process to the vertically aligned side walls of the spaced apart pumping sections 22b. The conduit members 36' and 37' serve to provide a path for current fiow to and from the pumping sections during the operation of the electromagnetic pump 20. The path for current flow from the conduit member 36, through the pumping sections 22b and to the conduit member 37 is completed by a conduit member 36a (FIGURE 12). The conduit member 36a is a U-shaped member which is joined to the walls of the upper and lower pumping sections in a manner analogous to the conduit members 36 and 37.

In the embodiment illustrated in FIGURES 11 and 12 the field coils 24' and 26 and the current carrying conduit members 36 and 37' are illustrated as being separately excited from sources 30' and 30". This configuration of pump components is not critical however, and minor modifications in the structural features of the pump 20 could be readily accomplished so that the field coils and conduit members are arranged to provide a seriesparallel path for current flow therethrough in a manner similar to the previously described embodiment.

Each of the pumping components utilized in the alternate embodiment disclosed in FIGURES 11 and 12 is constructed in substantially the same manner as the corresponding components which make up the pump 20. That is, the field coils 24' and 26' and the conduit members 36', 36a and 37' are thin walled chambers which are constructed of a material such as niobium and contain a lightweight medium which is substantially more conductive than niobium (i.e., lithium).

In operation, current from the source 30' flows through the parallel conductive paths provided by the lithium metal contained within the niobium chambers that constitute the field coils 24' and 26. The concomitant passage of current through the field coils results in the generation of a composite axial magnetic field which passes through the spaced apart pumping sections 22b in a downward direction substantially perpendicular to these members. As previously described this generated axial magnetic field constitutes one of the thrust producing components which effects the pumping of liquid metal coolant through the pumping sections 22b of the electromagnetic pump.

As described in conjunction with the first embodiment illustrated in FIGURES 1 through 9, the second thrust producing component is provided by the passage of current through the liquid metallic medium confined with in the pumping sections 22b. Current is supplied to these pumping sections from the source 30" and passes through the conduit member 36', the metallic medium confined within the upper pumping section 2217' and through the U-shaped conduit member 36a. The structural configuration of the conduit member 36a is such that the current passing from this member flows through the lower pumping section 22b in a direction opposite to the current passed through the upper pumping section, and thereafter passes through the conduit member 37' to the source 30".

Current flowing through the metallic medium confined within the upper pumping section coacts with the magnetic field passing therethrough to impart a longitudinal thrust to the metallic medium in the direction of the curved or reversing segment 220'. Similarly, current flowing through the metallic medium confined within the lower pumping section 22b coacts with the magnetic field to impart a longitudinal thrust to the metallic medium to effect a pumping thereof away from the reversing segment 22c and toward the tubular supply line 23. This utilization of each of the oppositely directed current components results in the production of a pressure head which is somewhat greater than that realized with the previously described embodiment.

A pump having the general characteristics of either of the two embodiments hereinbefore described can effectively pump liquid metals at a rate of approximately 200 gallons per minute in an environment having temperatures in excess of 2000 F. At these temperatures the alkali metals contained in the terminals, field coils and conductive members are in a liquid state. The rate of flow or pumping capacity is realized when an axial magnetic field having a flux density of approximately 425 gausse is directed normal to the pumping section or sections of the pumping duct wherethrough a current of approximately 1350 abamperes is passed.

The foregoing descriptions of two embodiments of a compact and lightweight electromagnetic pump, which utilize lightweight field coil materials to establish a force producing magnetic field, are simply illustrative of the application of the invention. Numerous modifications of the apparatus can be devised by those skilled in the art without departing from the spirit or scope of the invention. For example, the separation between the field coils might be continuously varied as the radius of the coils increases to form a dished coil so as to generate a constant magnetic field flux distribution over the effective area of the field coil assembly. Moreover, several sets of field coils of varying radii and current capacity could be selectively positioned and suitably separated to obtain other desired magnetic flux distribution patterns across the pumping section or sections of the pumping duct wherethrough a liquid metal is being circulated.

Still another configuration for a direct current conduction type electromagnetic pump embodying the principal features of the invention might include a circular pumping duct to take advantage of the peak magnetic field generated by a field coil assembly that would preferably be located outside the circular duct. Such a configuration could lead to substantial savings in the amount of field coil power required to effect an eflicient pumping operation. Various other modifications which would be apparent to one skilled in the art might include stacking a number of fluid carrying ducts alternately with current carrying conductive members connected thereto and interposed therebetween, or stacking the pumping sections of the ducts so that alternate ducts function as the current carrying conductive members in and of themselves.

From the foregoing it can be seen that certain obvious advantages result from the utilization of an electromagnetic pump embodying the structural features specifically described or obvious modifications thereof. The elimi nation of ferromagnetic core materials not only results in a reduction of weight but allows the pump to operate effectively at temperatures in excess of the Curie temperature of ferromagnetic materials. Moreover, the use of an alkali metal as the conductive medium within the field coil assembly and the conductive members further results in a weight reduction of the pumping unit. This additional weight reduction stems from the fact that the conductivity per unit weight of the alkali metal is approximately three times greater than that of copper, which has been used in previously developed D.C. electromagnetic pumps to provide the necessary path for current flow to the metalized fluid being pumped thereby. In addition, the thin walled construction of the various pump components, which are subsequently filled with the conductive alkali metal, facilitates the attachment of these lightweight members in the desired pumping configuration by a suitable welding process and overcomes the problems incident to high temperature brazing or soldering of heavy pper bus bars to a thin walled pumping & section wherethrough a metalized fluid is to be pumped.

Although a preferred embodiment of the invention has been described as constructed of a number of lightweight members arranged in a certain configuration and having certain approximate dimensions, it is apparent that other materials, configurations and dimensions can be advantageously utilized without deviating from the invention, various features of which are set forth in the following claims.

What is claimed is:

1. An electromagnetic device for pumping a metalized fluid through a thin walled fluid carrying conduit, which device comprises a pair of spaced apart hollow core field coils disposed in parallel relation on opposite sides of the fluid carrying conduit and arranged so as to produce an axial magnetic field substantially perpendicular to the direction of fluid flow within the conduit upon passage of current through said field coils, a pair of substantially non-conductive chamber defining members containing an alkali metal and secured to the fluid carrying conduit so as to provide a complete path for current flow therethrough substantially perpendicular to the direction of fiuid flow within the conduit and the magnetic field produced by said field coils, said non-conductive chamber defining members being formed of a lightweight material capable of withstanding high temperatures, and means supplying current to said hollow core field coils and the alkali metal within said chamber defining members so that an axial magnetic field is generated perpendicular to the current passing through the metalized fluid within the chamber, the mutually perpendicular magnetic field and current flow coacting to impart a thrust to the fluid in the conduit member and effect the pumping thereof.

2. An electromagnetic device for pumping a metalized fluid through a rectangular conduit member and along a first axis of a three dimensional coordinate system, which device comprises a Helmholtz type field coil assembly including a pair of lightweight circular hollow core field coils disposed on opposite sides of the conduit member for generating a magnetic field therethrough and along a sec- 0nd axis of the three dimensional coordinate system, and a pair of substantially non-conductive chamber defining members formed of a lightweight material capable of withstanding high temperatures and electrically connected in series with said field coil assembly, said non-conductive chamber defining members containing alkali metal and being secured to oppositely disposed sides of the conduit member to provide a complete path for current flow from said field coils through the metalized fluid contained in the conduit member and along a third axis of the three dimensional coordinate system, the mutually perpendicular magnetic field and current flow coacting to impart a thrust to the fluid within the conduit member and effect the pumping thereof when current is supplied to said field coil assembly and the conductive medium within said chamber defining members.

3. An electromagnetic device for pumping a metalized fluid through a rectangular fluid carrying conduit member, which device comprises a pair of spaced apart circular hollow core field coils disposed in parallel relation on opposite sides of the rectangular conduit member and arranged so as to produce a composite axial magnetic field through and substantially perpendicular to the direction of fluid flow within the conduit member upon passage of current through said field coils, said field coils including a substantially non-conductive thin walled outer shell formed of a lightweight material capable of withstanding high temperatures and being filled with a conductive alkali metal, a first current carrying member secured to one side wall of the rectangular conduit member, a second current carrying member secured to the oppositely disposed side wall of the rectangular conduit member, said current carrying members having a closed substantially non-conductive outer shell and being filled with a conductive alkali metal, said field coils being electrically connected in parallel and serially connected to said current carrying members so that a path for current flow is provided from said field coils through said first current carrying member and the metalized fluid contained in said conduit to said second current carrying member, and means selectively supplying current to said serially connected field coils and current carrying members so that current flow is established through the metalized fluid within said rectangular conduit member in a direction transverse of the magnetic field established by said field coils, the mutually perpendicular magnetic field and current flow coacting to impart a thrust to the fluid within the conduit member and efiect the pumping thereof.

4. An electromagnetic device for pumping a metalized fluid through a pair of vertically aligned, spaced-apart pumping sections of a thin walled fluid carrying pumping duct; which device comprises a pair of hollow core field coils disposed about the spaced-apart pumping sections of the pumping duct; means supplying current to said hollow core field coils so that a magnetic field is generated thereby through the spaced-apart pumping sections; the fluid flow through a first of the spaced-apart pumping sections being directed along a path substantially normal to the generated magnetic field; the fluid flow through a second of the spaced-apart pumping sections being parallel but oppositely directed to the fluid flow through the first pumping section; a plurality of substantially non-conductive chamber defining members secured to said spaced-apart pumping sections; said chamber defining members having a closed substantially nonconductive lightweight outer shell capable of withstanding high temperatures and being filled with an alkali metal so as to provide a series path for current flow through the spaced apart pumping sections; and means supplying current to the alkali metal contained within said non-conductive chamber defining members and the metalized fluid within the spaced-apart pumping sections of the duct; the current components passing through the pumping sections being oppositely directed and coacting with the mutually perpendicular magnetic field components to impart individual but cumulative thrust forces to the metalized fluid within the pumping duct.

References Cited in the file of this patent UNITED STATES PATENTS 2,637,207 De Boisblanc May 5, 1953 2,715,190 Brill Aug. 9, 1955 2,715,686 Asti Aug. 16, 1955 

1. AN ELECTROMAGNETIC DEVICE FOR PUMPING A METALIZED FLUID THROUGH A THIN WALLED FLUID CARRYING CONDUIT, WHICH DEVICE COMPRISES A PAIR OF SPACED APART HOLLOW CORE FIELD COILS DISPOSED IN PARALLEL RELATION ON OPPOSITE SIDES OF THE FLUID CARRYING CONDUIT AND ARRANGED SO AS TO PRODUCE AN AXIAL MAGNETIC FIELD SUBSTANTIALLY PERPENDICULAR TO THE DIRECTION OF FLUID FLOW WITHIN THE CONDUIT UPON PASSAGE OF CURRENT THROUGH SAID FIELD COILS, A PAIR OF SUBSTANTIALLY NON-CONDUCTIVE CHAMBER DEFINING MEMBERS CONTAINING AN ALKALI METAL AND SECURED TO THE FLUID CARRYING CONDUIT SO AS TO PROVIDE A COMPLETE PATH FOR CURRENT FLOW THERETHROUGH SUBSTANTIALLY PERPENDICULAR TO THE DIRECTION OF FLUID FLOW WITHIN THE CONDUIT AND THE MAGNETIC FIELD PRODUCED BY SAID FIELD COILS, SAID NON-CONDUCTIVE CHAMBER DEFINING MEMBERS BEING FORMED OF A LIGHTWEIGHT MATERIAL CAPABLE OF WITHSTANDING HIGH TEMPERATURES, AND MEANS SUPPLYING CURRENT TO SAID HOLLOW CORE FIELD COILS AND THE ALKALI METAL WITHIN SAID CHAMBER DEFINING MEMBERS SO THAT AN AXIAL MAGNETIC FIELD IS GENERATED PERPENDICULAR TO THE CURRENT PASSING THROUGH THE METALIZED FLUID WITHIN THE CHAMBER, THE MUTUALLY PERPENDICULAR MAGNETIC FIELD AND CURRENT FLOW COACTING TO IMPART A THRUST TO THE FLUID IN THE CONDUIT MEMBER AND EFFECT THE PUMPING THEREOF. 